On Thu, Jun 02, 2016 at 09:25:19AM +0900, Minchan Kim wrote:
> On Wed, Jun 01, 2016 at 04:09:26PM +0200, Vlastimil Babka wrote:
> > On 06/01/2016 01:21 AM, Minchan Kim wrote:
> >
> > [...]
> >
> > >
> > > Cc: Sergey Senozhatsky <sergey.senozhat...@gmail.com>
> > > Signed-off-by: Minchan Kim <minc...@kernel.org>
> >
> > I'm not that familiar with zsmalloc, so this is not a full review. I was
> > just curious how it's handling the movable migration API, and stumbled
> > upon some things pointed out below.
> >
> > > @@ -252,16 +276,23 @@ struct zs_pool {
> > > */
> > > #define FULLNESS_BITS 2
> > > #define CLASS_BITS 8
> > > +#define ISOLATED_BITS 3
> > > +#define MAGIC_VAL_BITS 8
> > >
> > > struct zspage {
> > > struct {
> > > unsigned int fullness:FULLNESS_BITS;
> > > unsigned int class:CLASS_BITS;
> > > + unsigned int isolated:ISOLATED_BITS;
> > > + unsigned int magic:MAGIC_VAL_BITS;
> >
> > This magic seems to be only tested via VM_BUG_ON, so it's presence
> > should be also guarded by #ifdef DEBUG_VM, no?
>
> Thanks for the point.
>
> Then, I want to change it to BUG_ON because struct zspage corruption
> is really risky to work rightly and want to catch on it in real product
> which disable CONFIG_DEBUG_VM for a while until make the feature stable.
Andrew,
Please fold this patch into zsmalloc: page migration support.
Thanks!
>From 6b8fa9889b7892bdf5b2f01698310cfc766c4d17 Mon Sep 17 00:00:00 2001
From: Minchan Kim <minc...@kernel.org>
Date: Fri, 3 Jun 2016 09:54:03 +0900
Subject: [PATCH] zsmalloc: zspage sanity check
The zsmalloc page migration is new feature so I want to catch any
corruption of zspage struct which is very critical to work
regardless of CONFIG_DEBUG_VM.
Signed-off-by: Minchan Kim <minc...@kernel.org>
---
mm/zsmalloc.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index a80100db16d6..f75d2d134741 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -523,7 +523,7 @@ static void get_zspage_mapping(struct zspage *zspage,
unsigned int *class_idx,
enum fullness_group *fullness)
{
- VM_BUG_ON(zspage->magic != ZSPAGE_MAGIC);
+ BUG_ON(zspage->magic != ZSPAGE_MAGIC);
*fullness = zspage->fullness;
*class_idx = zspage->class;
@@ -857,7 +857,7 @@ static struct zspage *get_zspage(struct page *page)
{
struct zspage *zspage = (struct zspage *)page->private;
- VM_BUG_ON(zspage->magic != ZSPAGE_MAGIC);
+ BUG_ON(zspage->magic != ZSPAGE_MAGIC);
return zspage;
}
--
1.9.1
